Before I became observant I davened in a non orthodox shul and davened Nusach Ashkenaz. For the past few years I have been going to a Chabad shul and have davened Nusach Ari. I now realize that Chabad is not for me. Can I switch back to Nusach Ashkenaz with or without a Hatarat Nedarim?
The answer is complicated. As a rule, if by your father's or grandfather's the Nusach was Ashkenaz while davening, there is no doubt you can daven Nusach Ashkeanz. If they used to daven Sfarad (Chassidic), it is better you continue davening in that Nusach. In any case if you daven in a shul that is Nusach Ashkenaz, you may continue davening Ashkenaz. If your shul is Sfarad, and your family custom is Sfarad, and you want to switch to Ashkenaz, you should do Hatarat Nedarim. Rabbi Eliezer Melamed